The convenience, efficiency, and safety of weight-training exercise machines is widely recognized. Popular weight-training exercise machines feature single or multiple stations at which a user may perform one or a variety of exercises for developing and toning different muscle groups of the user's body. One of the stations typically allows a user to perform a variety of exercises, including “press” and “shrug” exercises which train muscles of the upper body, including chest, shoulder, and arm muscles, and “squat” and “calf” exercises which train muscles of the legs.
For example, FIG. 1 is an elevational view of an exercise machine 100 having a weight stack 102 and a lift arm 104. The lift arm 104 includes a first end coupled to a fixed support 105, and a second end having a pair of handles 109. The weight stack 102 includes a plurality of weights 103, each of which is slideable on a pair of guide rods 106 (only one visible). The guide rods 106 include a lower end 107 pivotably coupled to a fixed base 108. With the lift arm 104 in a lowered position 110, the guide rods 106 are in an approximately vertical position. A selector pin 112 is inserted into the weight stack 102 to select a desired number of lifted plated 114. Exercise machines of the type shown in FIG. 1 are disclosed, for example, in U.S. Pat. No. 5,336,148 to Ish, incorporated herein by reference.
In operation, a user (not shown) may perform a “press” exercise by lying on a bench 111 and grasping the handles 109. The user then applies a training force to the handles 109 by pressing the handles 109 away from the user's chest. As the user overcomes the gravitational force on the lifted plates 114, the handles 109 move along a fixed arc 116, moving the lift arm 104 into a second position 120. As the handles 109 move along the arc 116, the lifted plates 114 move upwardly along the guide rod 106 and the guide rods 106 pivot into a tilted, non-vertical position 122. The shape and location of the arc 116 defined by the movement of the handles 109 is fixed. As shown in FIG. 2, the above-described press exercise trains a muscle zone 132 of a user's upper body 130.
Other known exercise machines allow greater freedom of movement of the handles of the lift arm. For example, FIG. 3 is an elevational view of an exercise machine 150 having a press station 152 and a pull-down station 154. The press station 152 includes a seat 153 and a lift arm 154. The lift arm 154 includes a first end pivotably attached to a support arm 155 by a hinge 157 and a second end proximate the seat 153 having a pair of handles 156. In a lowered position 180, the hinge 157 is engaged against a support frame 162.
The exercise machine 150 further includes a weight stack 158 slideably engaged with a weight guide 160, allowing the user to select a desired training load. A cable-and-pulley device 170 operatively couples the lift arm 154 to the weight stack 158 to apply a lifting force to the training load when a user applies a training force to the handles 156. Exercise machines of the type shown in FIG. 3 are disclosed, for example, in U.S. Pat. No. 4,986,538 to Ish, incorporated herein by reference.
As shown in FIG. 3, the cable-and-pulley device 170 includes a cable 172 having a first end attached to the weight stack 158. The cable 172 is trained over a first pulley 178 attached to an upper end of the load guide 160. As fully described in the ‘538 patent, the first cable 172 is coupled to a second cable by a first double floating pulley (not shown), which is in turn coupled to a third cable 173 by a second double floating pulley (not shown). The third cable 173 is trained over a second pulley 174 and is attached to the lift arm 154. Generally, a variety of cable-and-pulley device configurations may be used, including, for example, the cable-and-pulley device configurations disclosed in U.S. Pat. No. Re. 34,572 to Johnson and Ish, U.S. Pat. No. 5,971,896 to Gianelli et al, and U.S. Pat. No. 5,928,112 to Jones et al.
In operation, a user sits on the seat 153 and applies a training force on the handles 156. As shown in FIG. 3, as the user overcomes the gravitational force on the training load, the handles 156 may be moved throughout a training zone 186 approximately defined by the lowered position 180, an intermediate position 182, and a raised position 184. Because the hinge 157 is not rigidly attached to the support frame 162, the handles 156 are not constrained to follow a fixed arc, but rather, may freely move throughout the training zone 186 as the training load is raised by the user.
Beneficial results have been achieved using the above-described exercise machines. In some cases, however, it may be desirable to augment these beneficial results by increasing the amount of work the user must perform during press exercises. Increasing the work performed by the user may be desirable, for example, to expand the scope of the trained muscle zone, to more thoroughly train the muscle zone, or to train additional or secondary muscles not typically trained by conventional press exercise machines.